Patent EP0350909A2 successfully refreshed from Google Patents.
EP0350909A2
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EP
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Electrostatic liquid spray application of coatings with supercritical fluids as diluents and spraying from an orifice
Assignee: Union Carbide Corp
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Filing: 1989-07-13
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Granted: —
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Expires: 2009-07-13
Abstract
Abstract An electrostatic liquid coatings application process and apparatus is provided in which supercritical fluids, such as supercritical carbon dioxide fluid, are used to reduce to application consistency viscous coatings compositions to allow for their application as liquid sprays. The coatings compositions are sprayed by passing the composition under pressure through an orifice into the environment of the substrate. The liquid spray is electrically charged by applying a high electrical voltage relative to the substrate and electric current.
Inventors
- 👤 Kenneth Look Hoy
- 👤 Kenneth Andrew Nielsen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 14:29
CPC Classifications
B; B05; B05D; B05D1/00; B05D1/02; B05D1/025; C; C09; C09D; C09D7/00; B05D1/04; B05D2401/00; B05D2401/90; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/54
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
106 words
A process for electrostatic liquid spray application of coatings to a substrate by spraying onto the substrate under pressure a liquid mixture in a closed system, and electrically charging the liquid mixture by a high electrical voltage relative to the substrate and electric current, the liquid mixture comprising: (a) at least one polymeric component capable of forming a coating on a substrate; and (b) a solvent component containing at least one supercritical fluid, in at least an amount which when added to (a) is sufficient to render the viscosity of the mixture to a point suitable for spray application; and curing the coating in the substrate.
Claim 2
Dependent Claim
106 words
A process for electrostatic liquid spray application of coatings to a substrate by spraying onto the substrate under pressure a liquid mixture in a closed system, and electrically charging the liquid mixture by a high electrical voltage relative to the substrate and electric current, the liquid mixture comprising: (a) at least one polymeric component capable of forming a coating on a substrate; and (b) a solvent component containing at least one supercritical fluid, in at least an amount which when added to (a) is sufficient to render the viscosity of the mixture to a point suitable for spray application; and curing the coating in the substrate.
Claim 3
Dependent Claim
79 words
The process of Claim 1 wherein the liquid mixture is electrically charged internally by direct contact with a least one electrified surface before leaving a spray orifice or is electrically charged after leaving the orifice by electrical discharge from at least one external electrode located near the orifice and close to the spray or is electrically charged away from the orifice, by passing the liquid spray by or through external electrode before the spray is deposited onto the substrate.
Claim 4
Dependent Claim
42 words
The process of Claim 2 wherein the electrified surface is a wall of a conduit through which the liquid mixture flows, or a spray tip in a spray gun or an internal electrode that extends into the flow of the liquid mixture.
Claim 5
Dependent Claim
13 words
The process of Claim 3, wherein said external electrode is a metal wire.
Claim 6
Dependent Claim
25 words
The process of Claim 3, wherein the orifice size ranges from 0.1 to 1.8, preferably 0.1 to 0.635, especially 0.18 to 0.38 mm in diameter.
Claim 7
Dependent Claim
32 words
The process of Claims 1 to 5, wherein the spray pressure ranges from the critical pressure of the supercritical fluid to 345, preferably 738 - 207 bar, especially 82.8 - 172.5 bar.
Claim 8
Dependent Claim
30 words
The process of Claims 1 to 6, wherein the viscosity of the liquid mixture is less than 300 mPa.s, preferably 5 to 150 mPa.s, especially 10 to 50 mPa.s temperature.
Claim 9
Dependent Claim
32 words
The process of Claims 1 to 7, further comprising heating the liquid mixture to a temperature sufficient to prevent the adverse effect caused by rapid cooling when the liquid mixture is sprayed.
Claim 10
Dependent Claim
19 words
The process of Claim 8, wherein the liquid temperature ranges from 35° to 90°C, preferably from 45° to 75°C.
Claim 11
Dependent Claim
20 words
The process of Claims 1 to 9, wherein supercritical fluid comprises supercritical carbon dioxide fluid or supercritical nitrous oxide fluid.
Claim 12
Dependent Claim
28 words
The process of Claims 1 to 10, wherein the at least one polymeric component is selected from thermoplastic resins, thermosetting resins, crosslinkable film forming systems, and mixtures thereof.
Claim 13
Dependent Claim
43 words
The process of Claim 11, wherein the at least one polymeric component is selected from enamels, varnishes, lacquers, arylic resins, vinyl resins, styrenic resins, polyesters, alkyds, polyurethanes, urethanes, epoxies, phenolics, cellulosic esters, amino resins, natural gums, natural resins, and interpolymers and mixtures thereof.
Claim 14
Dependent Claim
33 words
The process of Claims 1 to 12, the liquid mixture further comprises pigments, pigment extenders, metallic flakes, fillers, drying agents, antifoaming agents, antiskinning agents, wetting agents, ultraviolet absorbers, cross-linking agents, and mixtures thereof.
Claim 15
Dependent Claim
21 words
The process of Claims 1 to 13, further comprising filtering the liquid mixture to remove particulates that would plug the orifice.
Claim 16
Dependent Claim
25 words
The process of Claims 1 to 14, further comprising promoting turbulent or agitated flow of the liquid mixture to aid atomization of the liquid spray.
Claim 17
Dependent Claim
32 words
The process of Claims 1 to 15, further comprising utilizing jets of compressed gas to assist formation and atomization of the liquid spray and to modify the shape of the liquid spray.
Claim 18
Dependent Claim
54 words
The process of Claim 16, wherein the compressed gas is compressed carbon dioxide, preferably in an amount of from 10 - 0.68 weight percent of the liquied mixture, or compressed nitrogen, helium, argon, xenon, and mixtures thereof or compressed air, preferably compressed air of lowered oxygen content to reduce flammability of said liquid spray.
Claim 19
Dependent Claim
24 words
The process of Claim 17, wherein the pressure of the compressed gas ranges from 0.345 - 5.52 bar, preferably from 0.345 - 1.38 bar.
Claim 20
Dependent Claim
28 words
The process of Claims 17 or 18, wherein the compressed gas is heated and has preferably a temperature of from 35 to 90°C, especially from 45 to 75°C.
Claim 21
Dependent Claim
29 words
The process of Claims 1 to 19, wherein the substrate is selected from metal, wood, glass, plastic, paper, cloth, ceramic, masonry, stone, cement, asphalt, rubber, and composite materials thereof.
Claim 22
Dependent Claim
33 words
The process of Claims 1 to 20, comprises the at least one active solvent in which the said polymer component is soluble and which is at least partially miscible with the supercriticyl fluid.
Claim 23
Dependent Claim
29 words
The process of Claim 21, wherein the solvent is selected from ketones, esters, ethers, glycol, ethers, glycol ether esters, alcohols, aromatic hydrocarbons, nitroalkanes, unsaturated hydrocarbons, halocarbons, and mixtures thereof.
Claim 24
Dependent Claim
15 words
The process of Claim 22, wherein the solvent component includes at least one hydrocarbon solvent.
Claim 25
Independent Claim
209 words
An apparatus for electrostatic liquid spray application of a coating to a substrate according to claims 1 to 23 comprising of, in combination (a) means for supplying at least one polymeric compound capable of forming a continuous, adherent coating; (b) means for supplying at least one active organic solvent; (c) means for supplying a supercritical fluid, preferably carbon dioxide fluid; (d) means for forming a liquid mixture of components supplied from (a) - (c); (e) means for spraying the liquied mixture onto a substrate by passing the mixture under pressure through an orifice into the enviroment of the substrate to form a liquid spray; (f) means for electrically charging the liquid by a high electrical voltage relative to the substrate and electric current and optionally; (g) means for heating any of the components of the liquid mixture and/or for heating the liquid mixture; (h) means for pressurizing the liquid mixture; (i) means for filtering said liquid mixture; (j) means for promoting turbulent or agitated flow of said liquid mixture to aid atomization of the liquid spray; (k) means for utilizing jets of compressed gas to assist formation and atomization of the liquid spray and to modify the shape of the liquid spray; (l) means for heating said compressed gas.
Claim 26
Dependent Claim
118 words
The apparatus of Claim 24 in which the means for electrically charging the liquid spray is at least one electrified surface that the liquid mixture contacts before leaving the orifice or at least one electrified external electrode, preferably a metal wire located near the orifice and close to the spray or an electrode system consisting of at least one external electrode located away from the orifice which the liquid spray passes by or through before being deposited onto the substrate and the electrified surface is a wall of a conduit through which the liquid mixture flows, or a spray tip in a spray gun or an electrified internal electrode that extends into the flow of said liquid mixture.
References Cited (Backward Citations)
No citation records indexed.
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